Fix QQuickControlPrivate::getContentItem() overrides

When no content item is explicitly assigned, container type of controls
(Page, Pane, Popup...) create a default content item on demand. Notice
that the content item is created from within the contentItem() getter,
so it must not emit contentItemChanged() to avoid binding loops.

QQuickControl::setContentItem_helper() was introduced in 1eaebd0 to
mitigate basically the same problem with QQuickScrollView, which has
its own special lazy creation of a Flickable content item.

Now, the problem is that the other container controls are not executing
setContentItem_helper(), because they have already assigned contentItem
and therefore it returns right away. Fix the issue by returning the new
content item without assigning it to let setContentItem_helper() do its
job. The issue was spotted while debugging QTBUG-61434.

Change-Id: Id6f84748ec08bbdfd3bd934dda627e2619af7d2a
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 3 insertions, 5 deletions

diff --git a/src/quicktemplates2/qquickpane.cpp b/src/quicktemplates2/qquickpane.cpp
index efa85e0c..b89131c4 100644
--- a/src/quicktemplates2/qquickpane.cpp
+++ b/src/quicktemplates2/qquickpane.cpp
@@ -114,7 +114,7 @@ QQuickItem *QQuickPanePrivate::getContentItem()
 {
     Q_Q(QQuickPane);
     if (!contentItem)
-        contentItem = new QQuickItem(q);
+        return new QQuickItem(q);
     return contentItem;
 }
 
@@ -206,8 +206,7 @@ void QQuickPane::setContentHeight(qreal height)
 */
 QQmlListProperty<QObject> QQuickPane::contentData()
 {
-    Q_D(QQuickPane);
-    return QQmlListProperty<QObject>(d->getContentItem(), nullptr,
+    return QQmlListProperty<QObject>(contentItem(), nullptr,
                                      QQuickItemPrivate::data_append,
                                      QQuickItemPrivate::data_count,
                                      QQuickItemPrivate::data_at,
@@ -229,8 +228,7 @@ QQmlListProperty<QObject> QQuickPane::contentData()
 */
 QQmlListProperty<QQuickItem> QQuickPane::contentChildren()
 {
-    Q_D(QQuickPane);
-    return QQmlListProperty<QQuickItem>(d->getContentItem(), nullptr,
+    return QQmlListProperty<QQuickItem>(contentItem(), nullptr,
                                         QQuickItemPrivate::children_append,
                                         QQuickItemPrivate::children_count,
                                         QQuickItemPrivate::children_at,